1. Field of the Invention
The present invention relates to the field of semiconductor manufacture, and more particularly, to a flash memory device and a manufacturing method thereof.
2. Description of the Prior Art
The flash memory device is a device capable of being electrically written and erased. In the flash memory device, two capacitors connected in serial are formed by arranging dielectric layers between a control gate, a floating gate, and a substrate, such that charges can be kept on the floating gate even when the device is shut off, and thereby providing memory function.
In order to improve the switching performance of the device, it is desirable to further increase capacitance between the control gate and the floating gate, whereby concentrating voltage on the capacitor formed by the floating gate and source/drain regions.